1. Field
Exemplary embodiments of the present invention relate to a semiconductor design technology and, more particularly, to a voltage generator and an image sensing device including the same.
2. Description of the Related Art
Semiconductor device operations require the use of various different voltages. However, since all the voltages that are used internally are not supplied from an external device, the semiconductor device has voltage generators for generating different internal voltages. The semiconductor device may include a voltage generator for boosting a power supply voltage VDD that is supplied from an external device to generate a boosted voltage VPP having a voltage that is higher than the power supply voltage VDD. The voltage generator includes a DC/DC converter.
One example of semiconductor devices that have a voltage generator are image sensing devices. Image sensing devices use the boosted voltage VPP in lieu of the power supply voltage VDD to improve operational reliability. For example, the image sensing device generates an operation control signal, which is used to transmit a photo-electric charge accumulated in a photodiode to a floating diffusion node, based on the boosted voltage VPP. As the transmission capability is improved when the photo-electric charge is transmitted to the floating diffusion node, the operational reliability of the image sensing device may be also improved.
An image sensing device captures images using the photosensitive properties of semiconductors. The image sensing device may be classified into charge coupled device (CCD) image sensors and complementary metal oxide semiconductor (CMOS) image sensors. The CMOS image sensors have come into widespread use. This is because CMOS image sensors allow for analog circuits and digital control circuits to be directly implemented on a single integrated circuit (IC).